In recent years, electrically powered vehicles, such as electric vehicles or the like have attracted a great deal of attention as a moving body that is environmentally friendly.
These electric vehicles have each an electric motor that generates a vehicle driving power and a rechargeable power storage battery that stores an electric power fed to the electric motor. However, the power storage batteries that are small in size and light in weight to be mounted in the electric vehicle are not large in storage capacity. Accordingly, users of the electric vehicles have to recharge the batteries at frequent intervals. Furthermore, for the recharging, the users have to handle a heavy charging cable, which is a troublesome work to the users.
One of methods of solution is a wireless power feeding that does not use an electric power source cable and a power feeding cable. A resonance method proposed by Non-Patent Document-1 mentioned below is able to effectively transfer an electric power for a remarkably long distance and thus the resonance method is collecting a lot of attention in recent years.
Furthermore, a wireless power feeding using self-resonant frequency via magnetic resonant coupling is described in Non-Patent Document-2 mentioned below, and power feeding apparatus of wireless type are described in Patent Documents-1, 2 and 3 mentioned below.